A Search for Physics Beyond the Standard Model Using Like-Sign Muon Pairs in Pp Collisions at Sqrt(s)
A Search for Physics Beyond the Standard Model Using Like-Sign Muon Pairs in Pp Collisions at Sqrt(s)

Author: Louise Anastasia Skinnari

Publisher:

Published: 2012

Total Pages: 424

ISBN-13:

DOWNLOAD EBOOK

This dissertation presents a search for physics beyond the Standard Model using pairs of muons with equal electric charge. The search is performed in a proton-proton collision data sample collected during 2011 at sqrt(s) = 7 TeV by the ATLAS experiment at the Large Hadron Collider. The total data sample corresponds to an integrated luminosity of 4.7fb-1. Events are selected by requiring pairs of prompt and isolated like-sign muons with transverse momentum greater than 20 GeV. The observed dimuon invariant mass distribution is compared to the Standard Model expectation, searching for any deviation between the observed and predicted yields. No evidence for an excess beyond the Standard Model expectation is observed. The results are interpreted as inclusive cross-section limits on the production of like-sign muon pairs from non-Standard Model sources as function of the dimuon invariant mass. The cross-section limits range between 30 fb and 1.2 fb. The data are also searched for a new narrow resonance which decays to like-sign muon pairs. No evidence for such resonant production is observed and the results are interpreted as upper limits on the mass and production cross section of doubly charged Higgs bosons. Assuming pair-production and a 100% branching ratio to muons, masses below 398 GeV (306 GeV) are excluded assuming coupling to left-handed (right-handed) fermions.

Search for Physics Beyond the Standard Model in Events with Two Leptons, Jets, and Missing Transverse Momentum in Pp Collisions at Sqrt(s)
Search for Physics Beyond the Standard Model in Events with Two Leptons, Jets, and Missing Transverse Momentum in Pp Collisions at Sqrt(s)

Author:

Publisher:

Published: 2015

Total Pages: 37

ISBN-13:

DOWNLOAD EBOOK

Our search is presented for physics beyond the standard model in final states with two opposite-sign same-flavor leptons, jets, and missing transverse momentum. The data sample corresponds to an integrated luminosity of 19.4 fb-1 of proton-proton collisions at √s = 8 TeV collected with the CMS detector at the CERN LHC in 2012. The analysis focuses on searches for a kinematic edge in the invariant mass distribution of the oppositesign same-flavor lepton pair and for final states with an on-shell Z boson. Furthermore, the observations are consistent with expectations from standard model processes and are interpreted in terms of upper limits on the production of supersymmetric particles.

Beyond The Standard Model Iv
Beyond The Standard Model Iv

Author: Tao Han

Publisher: World Scientific

Published: 1995-08-31

Total Pages: 650

ISBN-13: 9814549215

DOWNLOAD EBOOK

These proceedings contain over 100 talks on all aspects of Physics Beyond the Standard Model of the strong and electroweak interactions — ranging from Supersymmetry, Grand Unification, Technicolor, Exotic Particles, and CP Violation to Baryogenesis, Dark Matter, Strings and Black Holes — by leading authorities and the most active researchers in High Energy Physics. The goal of the conference is to provide a completely current summary of the most exciting and aesthetically appealing theoretical ideas, especially with regard to their predictions for yet undiscovered new particles, interactions and consequent phenomena. Particular emphasis is placed on current experimental limits and constraints on new physics, and on expectations and predictions regarding our ability to probe and discriminate between the many possibilities through experiments at present and future colliders in the decade(s) to come.

Search for Physics Beyond the Standard Model Using Multilepton Signatures in Pp Collisions at Sqrt(s)
Search for Physics Beyond the Standard Model Using Multilepton Signatures in Pp Collisions at Sqrt(s)

Author:

Publisher:

Published: 2011

Total Pages: 33

ISBN-13:

DOWNLOAD EBOOK

A search for physics beyond the standard model in events with at least three leptons and any number of jets is presented. The data sample corresponds to 35 inverse picobarns of integrated luminosity in pp collisions at sqrt(s) = 7 TeV collected by the CMS experiment at the LHC. A number of exclusive multileptonic channels are investigated and standard model backgrounds are suppressed by requiring sufficient missing transverse energy, invariant mass inconsistent with that of the Z boson, or high jet activity. Control samples in data are used to ascertain the robustness of background evaluation techniques and to minimise the reliance on simulation. The observations are consistent with background expectations. These results constrain previously unexplored regions of supersymmetric parameter space.

Physics In Collision - Proceedings Of The 15th International Conference
Physics In Collision - Proceedings Of The 15th International Conference

Author: Krzysztof Rybicki

Publisher: World Scientific

Published: 1996-01-23

Total Pages: 539

ISBN-13: 9814548057

DOWNLOAD EBOOK

This book presents a comprehensive overview of high energy physics. It covers the whole range of results from the colliders and fixed-target experiments as well as the astrophysics topics related to particle physics. Also discussed are the problems of proton structure, electroweak physics, non-perturbative QCD and heavy quarks.

Search for Physics Beyond the Standard Model in Events with a Z Boson, Jets, and Missing Transverse Energy in Pp Collisions at Sqrt(s)
Search for Physics Beyond the Standard Model in Events with a Z Boson, Jets, and Missing Transverse Energy in Pp Collisions at Sqrt(s)

Author:

Publisher:

Published: 2012

Total Pages:

ISBN-13:

DOWNLOAD EBOOK

A search is presented for physics beyond the standard model (BSM) in events with a Z boson, jets, and missing transverse energy (MET). This signature is motivated by BSM physics scenarios, including supersymmetry. The study is performed using a sample of proton-proton collision data collected at sqrt(s) = 7 TeV with the CMS experiment at the LHC, corresponding to an integrated luminosity of 4.98 inverse femtobarns. The contributions from the dominant standard model backgrounds are estimated from data using two complementary strategies, the jet-Z balance technique and a method based on modeling MET with data control samples. In the absence of evidence for BSM physics, we set limits on the non-standard-model contributions to event yields in the signal regions and interpret the results in the context of simplified model spectra. Additional information is provided to facilitate tests of other BSM physics models.